The term "high protein foods" used in this invention mainly means cheeses made from curds obtained by adding a coagulating agent to cow's milk such as whole milk or skim milk.
Curds, from which whey has been removed, are formable into a fibrous structure, but this property is extremely feeble. In view of this, the processes disclosed in Cheese and Fermented Milk Foods, 2nd Edition, or Japanese Patent Publication No. 30822/1980 have been publicly utilized for manufacturing torn dried fibrous structure chesses.
According to an example of these processes, a solidified curd is cut into small blocks by using a cutting means to thereby separate whey therefrom; next curd blocks are softened in hot water, taken out thereof and subjected to the orientation imparting treatment with mingling whereby to be made into a fibrous composition; and thereafter said curd is extruded under pressure through a conically tapered port by means of a screw or the like so as to have fiber strength.
The imparting of fiber strength to curds at the final step is achieved by the application of mechanical stress to curds using, for instance, the above mentioned process utilizing an extruder, an extending process utilizing an apparatus comprising differential rollers or the like.
In the case of increasing the fiber strength using these apparatuses, however, there take place unavoidable problems such that in the light of commodity design it is difficult to maintain the texture uniform and the shape stable, and further in the light of production technique it is difficult to increase the production capacity and reduce the range of change in commodity weights.
In other words, the use of the extruder facilitates the production of uniform-shaped commodities but is inferior in production capacity due to large pressure loss, while the use of the apparatus comprising differential rollers hinders the production of uniform-shaped commodities and is unable to obtain such commodities without lowering the production capacity. Such being the case, both apparatuses are defective in that they find difficulty in continuously producing commodities, which are high in fiber strength, uniform in texture and stable in shape, under an increased output.